Brass tonometer, for measuring ocular pressure in leather covered case, by Pickard and Curry, 195 Great Portland Street, London, England, 1870-1900.
Tonometers measure pressure within the eye. This is known as intraocular pressure. Glaucoma is a condition where the optic nerve becomes damaged leading to loss of sight. Glaucoma raises intraocular pressure. Tonometers were refined in the 1880s by German physiologist Adolph Eugene Fick (1829-1901). Cocaine was introduced as a local anaesthetic in 1887. This allowed tonometers to be applied directly to the cornea. This brass tonometer was made by instrument makers Pickard and Curry of London.